Buckingham Palace has instructed an external law firm to assist with its investigation into bullying allegations made against the Duchess of Sussex

Royal aides announced earlier this month that past and present employees of Meghan and Harry would be invited to speak in confidence about their experiences, after it was alleged she drove out two personal assistants and staff were “humiliated” on several occasions.

Now it is understood an outside legal company will help Buckingham Palace’s human resources team as it examines the circumstance of the allegations, first reported by the Times newspaper.

According to other reports, the Sussexes are not expected to be asked to contribute to the review, but the duchess has written to the palace asking for any documents, emails or texts relating to the allegations against her.

Lawyers for the duchess have denied the bullying allegations.

Harry was also accused of bullying, with the Times reporting earlier this month that a member of staff told a colleague the couple were “outrageous bullies”.

When the bullying allegations were first made, Buckingham Palace said in a statement it was “very concerned” about them, and stressed the Royal Household “does not and will not tolerate bullying or harassment in the workplace”.

It added: “Accordingly, our HR team will look into the circumstances outlined in the article. Members of staff involved at the time, including those who have left the Household, will be invited to participate to see if lessons can be learned.”

The investigation was launched after the Times reported that Jason Knauf, the Sussexes’ then communications secretary, made a bullying complaint in October 2018 in an apparent attempt to force Buckingham Palace to protect staff.

A source told the newspaper that Harry begged his senior aide not to take the matter further, but it also reported that lawyers for the duke and duchess deny the meeting took place and that Harry would not have interfered with staff matters.

Mr Knauf reportedly sent an email outlining the duchess’s alleged actions to Simon Case, the Duke of Cambridge’s then private secretary and now the cabinet secretary, after conversations with Samantha Carruthers, the head of human resources.

A Buckingham Palace spokesman said: “Our commitment to look into the circumstances around allegations from former staff of the Duke and Duchess of Sussex is being taken forward but we will not be providing a public commentary on it.”

A spokesman for the Sussexes declined to comment.

Soon after the bullying allegations were made, the monarchy was left reeling after Harry and Meghan’s interview with chat show host Oprah Winfrey, in which they made a string of allegations, including accusing a member of the royal family of making a racist comment about their son Archie.